Alright, well I've finally got enough money saved to get my big bore kit. I've been in communications with the boss man himself to order the 351 kit and pumper carb. I've found a nice build series on YouTube (MrDuhFactor) that pretty much takes you step by step through the process of disassembly, cleaning, and upgrading with reassembly.

What I would like to know is if there is anything else I should invest in or take a serious look at while I'll have the engine apart, and possibly out of the bike. I've finally seen the KACR (Kawasaki Automatic Compression Release, I'm assuming?) on the end of the exhaust cam, so I understand about disconnecting the spring. I'll have everything unplugged from the engine so I can deal with the 'smog' crap then and reroute a longer crankcase breather hose with filter either into the airbox or towards the rear of the bike. Anything I'm missing?

I do eventually plan on getting some different cams, although my mind may change after I get the 351 installed and I don't really know how to read the cams so I'll be doing plenty of researching and learning on that. Still wouldn't mind a kickstart, but that will come much later.

KLXster, I'm going to be asking questions about jetting again. haha I'll be using the BB pumper carb with the 351 for riding around my known areas, but I have a friend (Motovlogger LJ: The Friendly Hooligan) in KC, Mo that I would like to go ride with from time to time. I figure I'll keep the stock carb handy and have it tuned for riding around up there. Not sure if I'll go lidless when I do that, just depends on how things go the first time as it is.

Until then my friends and fellow riders, goodnight.

Lemon

 

Lemon, setting up the CVK for a 351 is beyond my data and knowledge. So, in general, just remember that going rich is safe for the engine - lean is destructive.. I could only offer guesses for your CVK setup - and my guesses would attempt to make sure the bike is running plenty rich.. You will hear other opinions that assume the 351 draws more fuel from standard CVK setups - those opinions also have no supporting data..

I certainly would have a long talk with Bill Blue about setting up the CVK.. Your exhaust system (When lidless) creates big HP and TRQ numbers in the upper range when properly fueled (using my setup recipe) on a stock bore with CVK.. I would assume the 351 would also have potential for big increases in the upper range as well..

 

Also Lemon, I don't remember any information in here regarding running a 351 with the KACR deactivated (spring removed, etc) ... Perhaps the 351 "gang" can provide you with this information - assuming one of them is running it deactivated.. It was only fairly recently that we finally determined that deactivation works just fine on a stock bore.. Of course, the issue with deactivation is whether or not it puts too great a strain on the starter..

 

I'll be keepin an eye on this thread since I plan to do the BB 351 kit during the mid Summer (to hot to ride) season year, if all goes as planned. Good luck with your project and please keep us posted. Remember, we love pics.....

 

Klxster, is your bike stock bore? I suppose I should have looked for that first. Oh well. Right now I'm still running the stage 2, and I'll just replace the stock carb with the Bill Blue kit once I get it. I just hate having to take everything apart to adjust the carb, so I figured that it would be easier to have a spare carb around and just swap out a whole system instead of changing pieces to one when/if I get to ride in KC.

It does seem to make sense that the 351 would necessitate more fuel, as it is bigger, therefore the same amount of fuel would cause it to run a little lean. At least in my thinking it does. As for the KACR, still hoping I got the acronym correct, I recall reading that it allowed the stock bore to start easier when disconnected. Figured it would do the same thing with the big bore. Better safe than sorry, right? For now I'll plan on leaving it connected.

Feel free Werloc!!! I'm definitely going to take pics, although I don't want to promise that it will literally be a step by step slideshow. I tend to get really focused once I get started doing something like this. I do have a GoPro and a JVC video recorder that I'm going to attempt to use while being plugged in so I don't run the battery down. The GoPro will probably be mounted somewhere, and I'll use the JVC for close up shots. As far as learning/spectating goes, the video link below is one that REALLY helped me as I was looking around for the same thing you seem to be in search of. He's got multitudes of videos just for this bike/engine that he did a complete tear down and build up on. This one is specifically the big bore kit build though. Enjoy

 

I just did my 351 and tm36-68 pumper. Only used the write ups here and of course factory manual. Search my name for numerous helpful posts from others, and both Dan

https://www.kawasakiforums.com/forum...s-links-32538/

And armycopter have great write ups. As others told me, take your time, label stuff, take pics for reference, and don't drop **** into the abyss lol...

I found the hardest, most time consuming part is reinserting the new piston and rings in the cylinder. I did it off the bike, and a second set of hands helped me put wrist pin in.

 

Clearly the person to go to on the 34mm carb if you are buying it with the kit would be the guy who modified it to work. There is a lot here on the TM36-68 if you search.

I wouldn't be too concerned with the starter. It spins so easily with the 250 after deactivating the KACR, especially in comparison to my 650 which is still using a compression release, that it would take a whole lot to strain it. I tried mine at single digit temps last winter and it spun easily. Displacement is less an issue than compression and I don't think the 351 is much more than stock if any. Plus in comparison, neither Honda nor Yamaha use compression releases on their 250s.

Of course "disabling" the KACR by either removing the spring or locking it disengaged with a metal rod always leaves it possible to put it back in service.

Have the valves re-seated (probably a check with DyKem to see they are seating properly) while apart, just to know it's all done, new seals and all. Have fun with the work.

 

On disabling the KACR, just remember that the 351 ups the compression, and you gain a bit more friction and weight with the bigger piston...not positive on the weight, however. These issues will put more stress on the starter. I have no doubt the starter will fire a 351 kitted bike with no issue without the KACR, I just don't think we know the long term effects at this point. It may or may not be an issue at all.

I don't guess I've studied the threads about just disconnecting the KACR spring, so I'm no expert there. However, vaguely recalling how my KACR looks, I'm not sure I'd want the lever flopping loosely. Did this method involve securing the counterweight in some manner? Again...I've not done this or considered it, so don't take my comments with any authority. That said, I find the KACR to be a non-issue in terms of letting it do its intended job and leaving it alone. If the bike has an issue starting, I say fix that instead of disconnecting the KACR starting aid. I ride alone often in some pretty remote areas out west where even getting a battery cable jump from a passerby is unlikely. I like keeping the starter and battery as healthy as possible, and the KACR eases some wear on both.

 

Lemon, the "instant starting" is a (fantastic) side effect of the MCM (Marcelino Cam Mod) and not from deactivating the KACR (Kawasaki Automatic Compression Release). Now, at this time, I believe the MCM is still not being recommended for use with the 351 - perhaps this is due to tight valve-to-piston clearance issues when used on a 351 but I can't remember so ask Bill Blue about that if you want to run MCM..

I do know that the MCM is a superior valve train setup over stock - contrary to some opinions you'll read and hear, it is more power everywhere.. It would certainly improve any big bore kit as long as there is no clearance issues.. Be aware that MCM increases valve overlap at TDC, so again, valve-to-piston clearances are something that you and Bill would need to talk about.

Regarding starter motor loading at startup - it will be harder on the starter to compress 351cc's compared to 250cc's at any given compression ratio. So, again, if someone in here can verify that the starter motor is up to this task, fine, otherwise you will be "blazing the trail" for current and future 351ers on this issue if you deactivate it..

 

When I did the 351 and pumper, all my hard start issues were gone! Getting the suspension done to me was the next best thing!